JPH0212067B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to a reading device. (Prior Art) Devices such as contact sensors have been developed as input devices for images and the like. One of the advantages of these devices is that they are easy to configure and can be used to store originals. For this purpose, in many cases, the substrate on which the photoelectric conversion element is provided is made movable relative to the document table, and, for example, a line type scan is repeated to read the entire screen of the document. In order to enable the substrate to be transported, the substrate is required to be lightweight. Therefore, in conventional reading devices, only a photoelectric conversion element is provided on a substrate, and the output from this element is supplied via a signal line to a processing circuit provided outside the substrate. According to such a configuration, the weight of the board itself is reduced, but due to the general demand for a wider reading area, the moving distance of the board becomes longer, and the signal lines also become longer. Also, as a matter of course, since the reading device is combined with other electronic equipment, it is placed in an environment where noise is likely to occur, and long signal lines are likely to pick up noise. (Problems to be Solved by the Invention) In this way, in the conventional technology, since the substrate on which the photoelectric conversion element is provided is movable, noise is easily picked up on the signal line, and the quality of the read signal is significantly degraded. It has declined. [Structure of the Invention] (Means for Solving the Problems) A circuit is provided that enables a substrate on which a photoelectric conversion element is provided to be moved and performs predetermined processing on a signal output from the photoelectric conversion element as the substrate is moved. In the reading device, the functions of the above circuit are divided, and circuits that implement some functions are installed on the board, and circuits that implement other functions are installed outside the board.Furthermore, both are connected with signal lines, and the circuits that implement some functions are installed on the board. The external circuit is characterized in that it is provided with means for integrating at least the input signal. (Function) According to the present invention, the output from the photoelectric conversion element is subjected to predetermined processing and then taken out from the substrate. This output signal is supplied to an external circuit via a signal line, but even if noise is discarded on this signal line, it is integrated by an integrating means provided within the external circuit. Therefore, the influence of noise is removed and a read signal of high quality can be obtained.Also, since the processing performed by the circuit provided on the board uses the output from the photoelectric conversion element as it is, more accurate processing can be achieved. (Example) Next, an example of the present invention will be described with reference to the drawings.The contact sensor in this example is capable of reading an A4 size color document.This contact sensor consists of a photoelectric conversion element, a transfer unit that transfers charges converted by the photoelectric conversion element, and a focusing rod lens array as an optical system capable of forming a one-to-one erect real image on the photoelectric conversion element. In this example, a device including a photoelectric conversion element and a charge-coupled device as a transfer section is a CCD (Charge
Coupled Device). These are formed on the same chip. Furthermore, in this embodiment, a photoelectric conversion element, that is, a photodiode, is formed of C--Si. This C--Si photodiode has a high photoelectric conversion speed of 1 msec or less. Furthermore, in the following explanation, the photoelectric conversion element will be referred to as a CCD sensor. This CCD sensor is provided with a pitch of 14 μm and 1
The chip has 2048 elements. like this
Eight CCD chips 11a to 11h are provided on a ceramic substrate 12 in a staggered manner as shown in FIG. The CCD chips 11a to 11h as a whole must have a length l=210 mm that covers at least the width of an A4 size sheet. Also, in this embodiment, each CCD chip 1
1a to 11h overlap d=2.38mm, which is CCD
This is equivalent to 170 sensor elements. For these CCD chips 11a to 11h, two focusing rod lens arrays 21a and 21b (trade name: Self-occurring lens, manufactured by Nippon Sheet Glass) are arranged in a V-shape, as shown in FIG.
Individual focusing rod lens arrays 21a, 21b
The length should be longer than the width of an A4 size document, and there should be 8 pieces.
It is assumed that the length is the same as the overall length of the CCD chips 11a to 11h. Also, the height h of the focusing rod lens arrays 21a and 21b is 20 mm in design.
50mm to 50mm is appropriate. This value is for increasing the depth of focus of the convergent rod lens arrays 21a, 21b. Especially at 50mm, the depth of focus is deep. Focusing rod lens array 21a, 21b
is usually plate-shaped. However, in this example, 2
The focusing rod lens array 21 is arranged so that the two focusing rod lens arrays 21a and 21b are engaged
Cut off the edges of a and 21b. In this way, by adjusting the angle of the slope to be cut, the angle formed by the two converging rod lens arrays 21a and 21b can be adjusted. Moreover, the space occupied by these convergent rod lens arrays 21a, 21b is reduced. However, the structure is designed to prevent light from entering through the carved slopes. Linear light sources 31a and 31b are required as contact sensors. The linear light sources 31a, 31b are provided with convergent rod lens arrays 21a, 2 as shown in FIG.
It is provided in parallel and close to 1b. The linear light sources 31a and 31b, the focusing rod lens arrays 21a and 21b, and the ceramic substrate 1
2 together constitute a contact sensor. This contact sensor is arranged so as to cross the document 32,
Read each line one by one. Light from the linear light sources 31a and 31b is irradiated onto one line of the original. The irradiated light is reflected on the original 32 and is reflected by the focusing rod lens arrays 21a and 21b.
The light is received by Focusing rod lens array 21
a and 21b form an image on the original 32 onto a CCD sensor. focusing rod lens array 21a,
21b has a large depth of focus, so even if the distance between the focusing rod lens arrays 21a, 21b and the document 32 is not constant and varies slightly, a clear image is formed on the CCD sensor. Furthermore, the convergent rod lens arrays 21a and 21b form images on the CCD sensor in a one-to-one manner without reducing the image on the original 32. Next, a specific and preferable structure will be explained. As shown in FIG. 4, CCD chips 11a to 11h
A lid 34 provided with windows 33a to 33h is attached to the board 11 on which the windows 33a to 33h are attached. This lid 34 does not allow light to pass through except from the windows 33a to 33h. window 3
3a to 33h are CCD chips 11a to 11h
It is set up correspondingly. For such a substrate 11 and lid 34, the fifth
Attach the support portion 35 as shown in the figure. This support portion 35 has holes 36 provided in the upper wall corresponding to the windows 33a to 33h. At the top of this hole 36,
The focusing rod lens arrays 21a, 2 are arranged so that the focusing rod lens arrays 21a, 21b are positioned.
1b is attached to the support part 35. On the other hand, this support part 35 has one linear light source 31.
Attach a together. As shown in FIG. 5, this linear light source 31a is designed so that light is emitted from only a portion thereof. That is, the window 37 is provided so that light from around a 45° angle to the original 32 is emitted. There is no light irradiation from other parts. Such a contact sensor detects the sixth position on the original 32.
arranged as shown in the figure. That is, the converging rod lens arrays 21a and 21b are arranged to face the original 32, and the window 37 of the linear light source 31a is arranged at an angle of 45 degrees with respect to the original 32. As shown in FIG. 6, the size of the contact sensor is such that the distance L from the document 32 to the substrate 12 is approximately 60 mm, and the distance w ₁ from the end of the support portion 35 to the end of the linear light source 31a is approximately 60 mm.
60 mm, and the distance w ₂ from the end of the support part 35 to the end of the lighting circuit 38 of the linear light source 31a is 100 mm. Next, the arrangement pitch of the CCD sensor will be explained. The resolution of the contact sensor in this example is 12 lines/mm
shall be. One pixel in this equation is approximately 84 μm. The size of this one pixel is determined by the CCD by focusing rod lens arrays 21a and 21b as shown in FIG.
It is also 84μm on the sensor. This CCD sensor is provided with a pitch of 14 μm (in effect,
The CCD sensor has a resolution of 72 lines/mm. ), so
Six element sensors are included in the size of one pixel. A fourth filter of white W, cyan C, and yellow Y is applied to the six elements that make up one pixel.
Attach two sheets at a time in this order as shown in the figure. However, a black filter is pasted on the 6 elements at the end. As will be described later, when attaching the filter in this embodiment, a considerable error is allowed compared to when attaching a single filter. Next, a circuit for processing signals from such a CCD will be explained. As shown in FIG. 5, this circuit includes an input section 51 , an integration section 52 that integrates the output from this input section 51 for each color, an amplification section 53 that amplifies the output from this integration section 52 , and an amplification section 53 that amplifies the output from this integration section 52. Part 5
A-D converts the output from 3 into a digital signal
It consists of a converting section 54 and a storage section 55 that stores the signal from the A-D converting section 54 . The input section 51 includes first to eighth CCD chips 11a to 11h that output serial signals, sampling and hold circuits 56a to 56h as zero level clamp circuits, and differential amplifiers 57a to 57h. 1 CCD chip 1
Each of the output signals 1a to 11h is input to each of sampling and hold circuits 56a to 56h and differential amplifiers 57a to 57h. Further, the outputs of the sampling and holding circuits 56a to 56h serve as another input to the differential amplifier. The integrating section 52 includes multiplexers 58a to 58h that separate the outputs of the differential amplifiers 57a to 57h for each color, and multiplexers 58a to 58h.
The output signals for each color from the integrators 591a and 591
b, 591c (corresponding to the output signal of the first CCD chip 11a, 592a, 592b, 592c (corresponding to the output signal of the second CCD chip 11a)
corresponding to the output signal of the CCD chip 11b), 593
a, 593b, 593c (third CCD chip 11
Corresponding to the output signal of c, 594a, 594b, 59
4c (corresponding to the output signal of the fourth CCD chip 11c), 595a, 505b, 595c (corresponding to the output signal of the fifth CCD chip 11c)
(corresponds to the output signal of CCD chip 11d), 596
a, 596b, 596c (6th CCD chip 11
corresponding to the output signal of e), 597a, 597b, 5
97c (corresponding to the output signal of the seventh CCD chip 11f), 598a, 598b, 598c (corresponding to the output signal of the eighth CCD chip 11f),
(corresponding to the output signal of the CCD chip 11g). The amplifying section 53 includes amplifiers 531a and 531a, which amplify the output signals for each color from the integrators 591a to 598c.
531b, 531c, 532a, 532b, 53
2c, 533a, 533b, 533c, 534
a, 534b, 535c, 536a, 536b,
536c, 537a, 537b, 537c, 53
8a, 538b, and 538c. The A-D converter 54 includes a selector 541a that switches and outputs signals amplified for each of the three colors in a time-division manner.
541h to 541h and the selectors 541a to 541
It consists of A/D converters 542a to 542h that convert analog signals from h to digital signals. The storage unit 55 has memories for white, cyan, and yellow, and is provided with two lines for each color, and stores the output signals of the A/D converters 542a to 542h. Now, regarding the operation of such a circuit, let's use the case of reading a white original as an example.
The explanation will focus on the output signal 1a. First to eighth CCD chips 11a to 11h
A pulse signal is supplied from a CCD scanning pulse generator (not shown). In synchronization with this pulse signal, signals photoelectrically converted by the CCD sensor are output from the CCD chips 11a to 11h. The signals serially output from the first CCD chip 11a are as shown in FIG.
For the dots, a black filter is pasted on the CCD sensor, so the voltage of the output signal is _V1 .
This voltage is the voltage associated with the dark current of the CCD sensor. Often 6 to 8 volts. On the other hand, W, Y, and C filters were pasted.
The voltage of the output signal of the CCD sensor is V ₁ ,
The amount of change is only on the order of 100mV. In the following, the voltage V ₁ will be referred to as the reference voltage. Among these signal groups, the signal from the CCD sensor to which the black filter is attached is held by the sampling hold circuit 56a. This sampling hold circuit 56a sends a signal having the reference voltage _V1 to the differential amplifier 57a until all output signals from the 2048 CCD sensors are sent to the differential amplifier 57a. Therefore, the differential amplifier 57a takes the difference between the voltage of the output signal from the CCD sensor to which the W, C, and Y filters are attached and the reference voltage, and at the same time appropriately amplifies this difference voltage. At this time, the output of the differential amplifier 57a is the output of the CCD with a W filter attached, as shown in FIG.
The signal 71W from the sensor, the signal 71Y from the CCD sensor to which the Y filter is attached, and the signal 71C from the CCD sensor to which the C filter is attached are successive in this order. However, these signals 71W, 71Y, and 71C are outputs from two CCD sensors. Therefore, the size of the small image reading pixel of the CCD sensor (resolution if color is not considered) at this time is 28 μm (36 lines/mm). These continuous analog signals are separated for each color in a multiplexer 58a. Figure 8a
A W filter as shown in is pasted.
The signal 71W from the CCD sensor is integrator 591a
Enter. Signal 7 from a CCD sensor with a Y filter attached as shown in Figure 8b
1Y is input to the integrator 591b. A signal 71C from the CCD sensor as shown in FIG. 8c is input to an integrator 591c. Charge is accumulated in capacitors (not shown) included in the integrators 591a, 591b, and 591c. Integrator 591 as shown in FIG.
Time when signals are input to a, 591b, 591c
Integral operation is performed during t ₀ . When the integration is finished,
The voltage value at this time as shown by the solid line in FIG. 9 is held and sent to amplifiers 531a, 531b, and 531c. Integrators 591a, 591b, and 591c have the following effects. For example, consider a case where noise is superimposed on the signal before inputting it to the integrators 591a, 591b, and 591c, as shown in FIG. 10. Such signals are transmitted to integrators 591a and 59
1b and 591c, as shown by the dotted line in FIG. 9, there is only a slight fluctuation in the integral value, and the influence of noise is almost eliminated. In this way, signals free from the influence of noise are supplied to amplifiers 531a, 531b, and 531c. The individual amplification factors of the amplifiers 531a, 531b, and 531c are adjusted so that the output voltages for each color are the same. Therefore, amplifiers 531a, 53
When the originals 1b and 521c are all white images, signals of the same voltage _V2 are output. Such a signal is supplied to the selector 541a. The selector 541a is a type of switch. This selector 541a performs a switch operation, that is, a switching operation, at a cycle twice as long as the cycle of the pulse signal from the CCD scanning pulse generator. Therefore, the selector 541a multiplexes and outputs time-divided signals as shown in FIGS. 14a, b, and c. The signals thus time-divided are supplied to the A/D converter 542a. three amplifiers 531a,
One A/D converter 542a is used in a time-division manner corresponding to 531b and 531c. The A/D converter 542a is expensive, and it is preferable to have fewer A/D converters. The output of the A/D converter 542a is stored in the storage section 55 . As described above, this storage unit 55 has memories 121W and 1 for each of white, yellow, and cyan.
21Y and 121C are available. Furthermore, this storage section 55 is provided with a gate. This gate corresponds to signal switching by selectors 541a to 541h. That is, the A/D converter 542a
The gates of the digital signals from 542h to 542h are opened according to the color of the filter attached to the CCD sensor, and the digital signals are stored in memories 121W, 121Y, and 121C for white, yellow, and cyan. The memories 121W, 121Y, and 121C do not store 2048×8 signals. As mentioned above, since filters of the same color are attached to the two CCD sensors, the number of signals is halved. Furthermore, since the signals are completely separated and stored for each of the three colors, the memories 121W, 121Y, 1 for each color are
The number of signals stored in 21C is further reduced to one-third. Therefore, the total memory for each color is 121W,1
21Y and 121C only need to have the ability to accommodate one-sixth the number of signals of all CCD sensors. Such memories 121W, 121Y for each color,
The signal stored in 121C is transmitted to read memories 122W, 122Y, 12 having the same storage capacity.
2C in parallel. When reading from the read memories 122W, 122Y, and 122C, the following precautions should be taken. As shown in FIG. 1, the first to eighth CCD chips 11a to 11h are spectroscopically overlapped on the scanning line for image reading, with a total of 170 CCD sensors. Therefore, it is necessary to read while removing this portion. In this embodiment, when the first and eighth CCD chips 11a to 11h are provided using the hybrid technology, the overlapping portion is known, so that the pixels corresponding to this overlapping can be removed. However, when referring to pixels on the CCD chips 11a to 11h,
6 pieces with W, C, and Y filters attached
Refers to a group of CCD sensors. For example, as shown in FIG. 13, the n-th pixel from the left end of the first CCD chip 11a is
A case will be explained in which the pixel does not overlap with the CCD chip 11b, but overlaps with the second CCD chip 11b from the (n+1)th pixel onward. In this embodiment, C filters are attached to all pixels after the (n+1)th pixel. Each of the memories 121W, 121Y, 121C and the readout memories 122W, 122Y, 122C stores one signal for one pixel. Therefore, CCD chip 1 from the (n+1)th
It is sufficient to remove signals up to the upper end pixel (referred to as the _n0th pixel) of 1a. This can be done by skipping it when reading. This skip is read out from the memory 122W, 122Y, 122C for each color.
Used when reading from. To identify overlapping parts, for example, for W signals, after hybridization, a CCD color sensor reads an original with a thin vertical line of about 80μ, converts the digital signal from the W memory into an analog value, and converts the digital signal from the W memory to an analog value. Since the output signal is obtained as two signals, this can be easily done by removing the address of the memory at the rear end of the CCD sensor so that it becomes one signal. Next, a description will be given of where the above circuits are placed. In this embodiment, the input section 51 is provided on the ceramic substrate 12. However, in FIG. 1, only the first to eighth CCD chips 11a to 11h are shown. The integrating section 52 , the amplifying section 53 , the A-D converting section, and the storage section 55 are connected to the substrate 1 constituting the contact sensor.
It is not provided on the substrate 12, but is provided outside the substrate 12. Then, these circuits and the input section 51 are electrically connected with a cord. The advantages of this are (i) CCD chips 11a to 11h, sampling and hold circuits 56a to 56h, differential amplifiers 57a to 57h, and linear light sources 31a and 3;
1b, focusing rod lens array 21a, 21
b is provided integrally with the substrate 12, so it is lightweight. (ii) Since the input section 51 is provided on the board 12,
Significant signal components from the board 12 are amplified, so the influence of noise is reduced, and (iii) the integration section 52 is provided in the circuit outside the board, so the influence of noise is reduced can be virtually eliminated. In this embodiment, an input section 51 provided on the board 12
As shown in FIG. Since the output is directly subjected to calculations before being output to the outside, the calculation itself is accurate, and the degree of freedom is high as it is not subject to any constraints. Furthermore, since filters of the same color are attached to the two CCD sensors, even if one CCD sensor has a defect, the signal from the other CCD sensor can be used. In fact, when 2048 CCD elements are formed on one chip, two or three defective elements often occur. In this case, the device was discarded as a defective product, but if it is used in this way, even if it is a defective device, it is essentially equivalent to there being no defective device. This is more effective when reading black and white originals. If there are no defects, using signals from two CCD sensors will increase the S/N. However,
One pixel may be read by three CCD sensors. At that time, use W, Y, and C filters one by one.
Paste it on the CCD sensor. When reading a black and white original, one pixel may be read by one CCD sensor. Furthermore, if filters of the same color are attached to one pixel, color separation can be ensured even if there is some error in attaching the filters. The circuit features of this embodiment are summarized as follows. (i) Strong against noise. (ii) Fewer A/D converters are required. (iii) It is possible to adjust the signal for each color. (iv) The number of components provided on the moving board is small and does not interfere with the movement of the board. The advantages of (i) and (iv) are related; the input section 51 extracts only the signal corresponding to the color and at the same time appropriately amplifies it.
The weight of the board is light because the only part is provided on the board. The signal obtained here is sent to the integrating section 52 via a signal line.
Therefore, even if noise is picked up by the signal line, the noise is eliminated by the integrating section 52. After the noise is eliminated, the amplification section 53 amplifies the signal, so that the influence of the noise does not appear. The advantage of (ii) is that it is used in time division. The advantage of (iii) is that an amplifier is provided for each color. Further, in this embodiment, signals are transferred using a CCD, and the CCD has a high transfer speed. Furthermore, when reading an A4-sized document, for example, it is better to use eight CCDs as in this embodiment than to use one CCD of this size because signal transfer is performed in parallel, so the transfer time is shorter. is short. The extra read signal is stored in the read memory 12 as described above.
All you have to do is select and read the signals from 2W, 122Y, and 122C, and it is a big task.
The time required for reading is the same as when one CCD is used. The embodiments of this invention have been described above, but
The present invention is not restricted in any way to the examples. In the embodiment, the photoelectric conversion element array and the transfer section are realized by a CCD, but a CTD (Charge Transfer Device) may also be used. For example, BBD
(Bucket Brigade Device), CID (Bharge
Injection Device), LCD (Light Coupled
device), PCD (Plasma Coupled Device), and scanter. Furthermore, the photoelectric conversion element arrays do not need to be arranged in a staggered manner, but may be arranged in three rows so as to cover the reading area, or may be arranged in any plurality. The optical system is not limited to a focusing rod lens array. The number of light sources is not limited, and may be one instead of two. Also, as a light source, fluorescent lamps,
It may also be an LED (Light Emitting Diode). [Effects of the Invention] As described above, according to the present invention, it is possible to obtain a read signal that is not affected by noise applied to the signal line. Furthermore, since a predetermined function is assigned to the circuit provided on the substrate, the output of the photoelectric conversion element is directly processed, and processing with a higher degree of freedom can be realized.

[Brief explanation of drawings]

1 to 16 show the contact sensor according to the embodiment, FIG. 1 shows the arrangement of eight CCD chips, and FIG. 2 shows the positional relationship between the CCD chips and the focusing rod lens array. A schematic perspective view showing the third
The figure is a schematic cross-sectional view of a contact sensor to explain image formation on a CCD chip, Figure 4 is an assembly diagram when configuring a substrate with a CCD chip as a contact sensor, and Figure 5 is a diagram of the contact sensor. A perspective view, FIG. 6 is a side view of the contact sensor shown in FIG. 5, and FIG. 7 is a side view of the contact sensor shown in FIG.
Figure 8 is a diagram showing how to attach a filter onto a CCD sensor, and Figure 9 is an electrical circuit diagram of this contact sensor.
14 to 14 are diagrams showing signals of various parts in this electric circuit diagram, FIG. 15 is a diagram showing a storage section, and FIG. 16 is a diagram showing overlapping of CCD chips. 11a, 11b, 11c, 11d, 11e, 1
1g, 11h...CCD chip, 21a, 21b...
Focusing rod lens array, 31a, 31b...linear light source.

Claims (1)

[Scope of Claims] 1. A light source, a substrate provided opposite to a document to which light from the light source is irradiated, a photoelectric conversion element provided on the substrate, and a photoelectric conversion element provided from the document to the photoelectric conversion element. an optical system arranged so as to receive reflected light; a means for relatively moving at least the substrate and the document; and a predetermined process for the output from the photoelectric conversion element as the means moves. In the reading device, a part of the circuit is provided on the substrate, other circuit components are provided outside the substrate, and the circuit components provided outside the substrate are connected to the substrate. A reading device connected to the reading device by a signal line, and further comprising an integrating means for integrating an input signal in the circuit outside the substrate.